Hi Frank,
Do you have any lash caps. If you install one on the valve top it should bottom out the lifter, the valve may be left open a bit but should not be enough to contact the piston.
On the 2.6 I use Chevy bushings and drill the cam to accept the 1/4" dowel.

Cheers, Charlie
If It ain't broke, Modify it!
87 Montero turbo Converted back in Spring1989
95 Montero SR 3.8 DOHC Only one?
93 Pajero 3 door 6G75 Mivec with paddle shifted 5 speed
Then a Gen2 SR with full coil independent suspension.